The present invention is directed to a flexible pipe saddle and more specifically to a flexible one piece saddle having an integral projecting boss for receiving a branch pipe, wherein the flexible pipe saddle will provide a fluid tight, sealed connection while accommodating different sized pipes and/or surface irregularities.
The principle problem with prior art connectors for connecting a branch pipe to a main pipe is the inability to provide a fluid tight sealed connection in view of variations in pipe diameter and/or surface irregularities. A number of prior art connecting systems utilized a connector member of flexible sealing material which was inserted in a hole drilled in the main pipe with a small flange overlying the surface of the main pipe. The connector member would be secured to the inner surface of the hole by means of an internal wedge or an expansible clamp as disclosed in the U.S. Pat. No. (3,406,988) to Jones and the U.S. Pat. No. (3,958,313) to Rossborough. The connector disclosed in U.S. Pat. No. (3,796,445) to Strott, was secured in the hole in the main pipe by means of sealing material forced into an annular recess between the connector and an outer skirt overlying the surface of the pipe. The system disclosed in U.S. Pat. No. (4,103,940) to Bills utilized a metallic connector with the inner end thereof deformed to provide a saddle and a pilot portion with the connector being brazed to a metallic main pipe. Since the aforementioned connectors are merely inserted into the hole in the main pipe and secured therein by pressure, adhesive means or brazing, the connection between the connector and the main pipe did not provide sufficient strength and stability for the rough usage generally associated with sewer pipes that are buried in the ground.
In order to provide a stronger, more stable connection between the connector and the main pipe a number of prior art systems provided rigid saddle members having a projecting, hollow, tubular boss portion in alignment with a hole in the main pipe and connecting means extending completely about the main pipe for anchoring the saddle in the proper position relative to the hole. Since the saddles were rigid and unyielding, it was necessary to provide a number of different size saddles to accommodate different size pipes or to provide a plurality of adapters for mating a saddle to different sized pipes. An example of a plurality of adapters is disclosed in U.S. Pat. No. (3,331,622) to Bagnulo. Furthermore, since the saddles were rigid and unyielding, it was always necessary to utilize a separate sealing member between the saddle and the main pipe to provide a fluid tight seal. The patent to Bagnulo utilizes such a separate sealing member, as do the Fowler U.S. Pat. No. (3,663,042), Henry U.S. Pat. No. (3,825,286), Acda U.S. Pat. No. (3,918,748), Blakely U.S. Pat. No. (3,999,785) and Acda U.S. Pat. No. (4,018,464).
In order to accommodate a saddle to different size mains, the Burnett U.S. Pat. No. (4,494,780) discloses a saddle formed of an elastomeric material having a hollow, tubular extension for receiving a lateral. A hollow, cylindrical casting surrounds the hollow, cylindrical projection and is connected to an adjustable strap at either side which extends about the main pipe, so that upon tightening of the strap, the casting will press down on the elastomeric saddle to deform the saddle into engagement with different size mains. Thus, distortion will vary depending upon the size of the main with significant bulging of the saddle. Such stresses frequently lead to failure of the saddle, thereby destroying the integrity of the fluid tight connection. Furthermore, for different size laterals, it is necessary to utilize separate saddles having hollow, tubular extensions of different sizes. The elastomeric saddle merely abuts against the surface of the main surrounding the hole cut in the main and there are no means provided for specifically locating the saddle relative to the hole prior to the tensioning of the strap to ensure that the saddle engages the main along a line which is spaced substantially equidistant from the periphery of the hole. In any event such spacing provides an impediment to the flow of fluids from the lateral into the main. The Jakobsen U.S. Pat. No. (4,107,454) discloses use of a resilient saddle of an elastomer or rubber material secured to the main by means of adjustable straps extending completely about the main and the saddle. However, no means are provided for locating the saddle relative to the hole and instead of a radially projecting hollow, tubular member for receiving a lateral, the saddle is provided with an axially extending aperture for the reception of a hose coupling to facilitate the introduction of a pressurized gas into the main conduit.
The use of plastics in the construction of saddles for connecting a lateral pipe to a main pipe is old and well known in the art as evidenced by Turner U.S. Pat. No. (3,432,188) and Smith U.S. Pat. No. (3,891,247). However, the plastic material disclosed in each of these patents is relatively rigid and a separate sealing ring is required in Turner while a complicated series of passages and recesses are required in the saddle of Smith to allow the fluid pressure within the pipes to create a sealing of the saddle to the main pipe.